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Liu H, Ma Y, Yu J, Chen X, Wang S, Jia Y, Ding N, Jin X, Zhang Y, Xu J, Li X. Insight into the regulatory mechanism of dynamic chromatin 3D interactions during cardiomyocyte differentiation in human. MOLECULAR THERAPY. NUCLEIC ACIDS 2023; 33:629-641. [PMID: 37650118 PMCID: PMC10462852 DOI: 10.1016/j.omtn.2023.07.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 07/28/2023] [Indexed: 09/01/2023]
Abstract
Cardiogenesis is an extremely complicated process involved with DNA regulatory elements, and trans factors regulate gene expression pattern spatiotemporally. Enhancers, as the well-known DNA elements, activate target gene expression by transcription factors (TFs) occupied to organize dynamic three-dimensional (3D) interactions, which when affected or interrupted might cause heart defects or diseases. In this study, we integrated transcriptome, 3D genome, and regulatome to reorganize the global 3D genome in cardiomyogenesis, showing a gradually decreased trend of both chromatin interactions and topological associating domains (TADs) during cardiomyocyte differentiation. And almost all of the chromatin interactions occurred within the same or between adjacent TADs involved with enhancers, indicating that dynamical rewiring of enhancer-related chromatin interactions in the continuous expansive TADs is closely correlated to cardiogenesis. Moreover, we found stage-specific interactions activate stage-specific expression to be involved within corresponding biological functions, and the stage-specific combined regulations of enhancers and binding TFs form connected networks to control stage-specific expression and biological processes, which promote cardiomyocyte differentiation. Finally, we identified markers based on regulatory networks, which might drive cardiac development. This study demonstrates the power of enhancer interactome combined with active TFs to reveal insights into transcriptional regulatory networks during cardiomyogenesis.
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Affiliation(s)
- Hui Liu
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, Heilongjiang 150081, China
| | - Yingying Ma
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, Heilongjiang 150081, China
| | - Jiaxin Yu
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, Heilongjiang 150081, China
| | - Xiang Chen
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, Heilongjiang 150081, China
| | - Shuyuan Wang
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, Heilongjiang 150081, China
| | - Yijie Jia
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, Heilongjiang 150081, China
| | - Na Ding
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, Heilongjiang 150081, China
| | - Xiaoyan Jin
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, Heilongjiang 150081, China
| | - Yunpeng Zhang
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, Heilongjiang 150081, China
| | - Juan Xu
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, Heilongjiang 150081, China
| | - Xia Li
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, Heilongjiang 150081, China
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2
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Renaud-Pageot C, Quivy JP, Lochhead M, Almouzni G. CENP-A Regulation and Cancer. Front Cell Dev Biol 2022; 10:907120. [PMID: 35721491 PMCID: PMC9201071 DOI: 10.3389/fcell.2022.907120] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 05/11/2022] [Indexed: 11/13/2022] Open
Abstract
In mammals, CENP-A, a histone H3 variant found in the centromeric chromatin, is critical for faithful chromosome segregation and genome integrity maintenance through cell divisions. Specifically, it has dual functions, enabling to define epigenetically the centromere position and providing the foundation for building up the kinetochore. Regulation of its dynamics of synthesis and deposition ensures to propagate proper centromeres on each chromosome across mitosis and meiosis. However, CENP-A overexpression is a feature identified in many cancers. Importantly, high levels of CENP-A lead to its mislocalization outside the centromere. Recent studies in mammals have begun to uncover how CENP-A overexpression can affect genome integrity, reprogram cell fate and impact 3D nuclear organization in cancer. Here, we summarize the mechanisms that orchestrate CENP-A regulation. Then we review how, beyond its centromeric function, CENP-A overexpression is linked to cancer state in mammalian cells, with a focus on the perturbations that ensue at the level of chromatin organization. Finally, we review the clinical interest for CENP-A in cancer treatment.
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3
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Verrelle P, Meseure D, Berger F, Forest A, Leclère R, Nicolas A, Fortas E, Sastre-Garau X, Lae M, Boudjemaa S, Mbagui R, Calugaru V, Labiod D, De Koning L, Almouzni G, Quivy JP. CENP-A Subnuclear Localization Pattern as Marker Predicting Curability by Chemoradiation Therapy for Locally Advanced Head and Neck Cancer Patients. Cancers (Basel) 2021; 13:cancers13163928. [PMID: 34439087 PMCID: PMC8391827 DOI: 10.3390/cancers13163928] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 07/28/2021] [Accepted: 07/29/2021] [Indexed: 12/11/2022] Open
Abstract
Simple Summary For clinicians, rapid diagnosis of early neoplastic lesions and prediction of treatment response are two key aspects to guide their choice of treatment. Current histological markers are based on proliferation, differentiation states or specific cell function, but do not take full advantage of tumor characteristics. We show that the subnuclear distribution of CENP-A, the centromeric histone variant, provides, for both aspects, information distinct from and independent of commonly used markers. Our study reveals that in locally advanced head and neck squamous cell cancer patients, the subnuclear distribution of CENP-A at the time of diagnosis is an independent predictive marker of local disease control and curability by concurrent chemoradiation therapy. We provide evidence for the clinical applicability of this CENP-A labeling as a cost-effective marker regardless of genetic alterations in the tumor, perfectly compatible with the clinical time constraints in the course of therapy. Abstract Effective biomarkers predictive of the response to treatments are key for precision medicine. This study identifies the staining pattern of the centromeric histone 3 variant, CENP-A, as a predictive biomarker of locoregional disease curability by chemoradiation therapy. We compared by imaging the subnuclear distribution of CENP-A in normal and tumoral tissues, and in a retrospective study in biopsies of 62 locally advanced head and neck squamous cell carcinoma (HNSCC) patients treated by chemoradiation therapy. We looked for predictive factors of locoregional disease control and patient’s survival, including CENP-A patterns, Ki67, HPV status and anisokaryosis. In different normal tissues, we reproducibly found a CENP-A subnuclear pattern characterized by CENP-A clusters both localized at the nuclear periphery and regularly spaced. In corresponding tumors, both features are lost. In locally advanced HNSCC, a specific CENP-A pattern identified in pretreatment biopsies predicts definitive locoregional disease control after chemoradiation treatment in 96% (24/25) of patients (OR = 17.6 CI 95% [2.6; 362.8], p = 0.002), independently of anisokaryosis, Ki67 labeling or HPV status. The characteristics of the subnuclear pattern of CENP-A in cell nuclei revealed by immunohistochemistry could provide an easy to use a reliable marker of disease curability by chemoradiation therapy in locally advanced HNSCC patients.
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Affiliation(s)
- Pierre Verrelle
- Institut Curie, PSL Research University, CNRS, Sorbonne Université, Nuclear Dynamics Unit, Equipe Labellisée Ligue Contre le Cancer, 26 rue d’Ulm, 75005 Paris, France;
- University of Clermont Auvergne, UFR Médecine, 63001 Clermont-Ferrand, France
- CNRS UMR 9187, INSERM U1196, Institut Curie, PSL Research University and Paris-Saclay University, 91405 Orsay, France
- Radiation Oncology Department, Institut Curie, 75005 Paris, France; (R.M.); (V.C.)
- Correspondence: (P.V.); (G.A.); (J.-P.Q.)
| | - Didier Meseure
- Platform of Experimental Pathology PATHEX, Institut Curie, 75005 Paris, France; (D.M.); (R.L.); (A.N.); (E.F.)
- Department of Diagnostic and Theranostic Medicine, Institut Curie, 75005 Paris, France
| | - Frédérique Berger
- Institut Curie, PSL Research University, Biometry Unit, 75005 Paris, France;
| | - Audrey Forest
- Institut Curie, PSL Research University, CNRS, Sorbonne Université, Nuclear Dynamics Unit, Equipe Labellisée Ligue Contre le Cancer, 26 rue d’Ulm, 75005 Paris, France;
| | - Renaud Leclère
- Platform of Experimental Pathology PATHEX, Institut Curie, 75005 Paris, France; (D.M.); (R.L.); (A.N.); (E.F.)
- Department of Diagnostic and Theranostic Medicine, Institut Curie, 75005 Paris, France
| | - André Nicolas
- Platform of Experimental Pathology PATHEX, Institut Curie, 75005 Paris, France; (D.M.); (R.L.); (A.N.); (E.F.)
- Department of Diagnostic and Theranostic Medicine, Institut Curie, 75005 Paris, France
| | - Emilie Fortas
- Platform of Experimental Pathology PATHEX, Institut Curie, 75005 Paris, France; (D.M.); (R.L.); (A.N.); (E.F.)
- Department of Diagnostic and Theranostic Medicine, Institut Curie, 75005 Paris, France
| | - Xavier Sastre-Garau
- Department of Pathology, Intercommunal Hospital Center of Creteil, 94000 Créteil, France;
| | - Marick Lae
- Department of Pathology, Centre Henri Becquerel, INSERM U1245, UNIROUEN, University of Normandie, 76031 Rouen, France;
| | - Sabah Boudjemaa
- Department of Pathology, Hôpital Armand Trousseau, 75012 Paris, France;
| | - Rodrigue Mbagui
- Radiation Oncology Department, Institut Curie, 75005 Paris, France; (R.M.); (V.C.)
| | - Valentin Calugaru
- Radiation Oncology Department, Institut Curie, 75005 Paris, France; (R.M.); (V.C.)
| | - Dalila Labiod
- Translational Research Department, Experimental Radiotherapy Platform, Institut Curie, PSL Research University, University Paris Saclay, 91400 Orsay, France;
| | - Leanne De Koning
- Department of Translational Research, Institut Curie, PSL Research University, 75005 Paris, France;
| | - Geneviève Almouzni
- Institut Curie, PSL Research University, CNRS, Sorbonne Université, Nuclear Dynamics Unit, Equipe Labellisée Ligue Contre le Cancer, 26 rue d’Ulm, 75005 Paris, France;
- Correspondence: (P.V.); (G.A.); (J.-P.Q.)
| | - Jean-Pierre Quivy
- Institut Curie, PSL Research University, CNRS, Sorbonne Université, Nuclear Dynamics Unit, Equipe Labellisée Ligue Contre le Cancer, 26 rue d’Ulm, 75005 Paris, France;
- Correspondence: (P.V.); (G.A.); (J.-P.Q.)
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Rausch C, Weber P, Prorok P, Hörl D, Maiser A, Lehmkuhl A, Chagin VO, Casas-Delucchi CS, Leonhardt H, Cardoso MC. Developmental differences in genome replication program and origin activation. Nucleic Acids Res 2021; 48:12751-12777. [PMID: 33264404 PMCID: PMC7736824 DOI: 10.1093/nar/gkaa1124] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 10/09/2020] [Accepted: 11/04/2020] [Indexed: 12/17/2022] Open
Abstract
To ensure error-free duplication of all (epi)genetic information once per cell cycle, DNA replication follows a cell type and developmental stage specific spatio-temporal program. Here, we analyze the spatio-temporal DNA replication progression in (un)differentiated mouse embryonic stem (mES) cells. Whereas telomeres replicate throughout S-phase, we observe mid S-phase replication of (peri)centromeric heterochromatin in mES cells, which switches to late S-phase replication upon differentiation. This replication timing reversal correlates with and depends on an increase in condensation and a decrease in acetylation of chromatin. We further find synchronous duplication of the Y chromosome, marking the end of S-phase, irrespectively of the pluripotency state. Using a combination of single-molecule and super-resolution microscopy, we measure molecular properties of the mES cell replicon, the number of replication foci active in parallel and their spatial clustering. We conclude that each replication nanofocus in mES cells corresponds to an individual replicon, with up to one quarter representing unidirectional forks. Furthermore, with molecular combing and genome-wide origin mapping analyses, we find that mES cells activate twice as many origins spaced at half the distance than somatic cells. Altogether, our results highlight fundamental developmental differences on progression of genome replication and origin activation in pluripotent cells.
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Affiliation(s)
- Cathia Rausch
- Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - Patrick Weber
- Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - Paulina Prorok
- Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - David Hörl
- Department of Biology II, LMU Munich, 81377 Munich, Germany
| | - Andreas Maiser
- Department of Biology II, LMU Munich, 81377 Munich, Germany
| | - Anne Lehmkuhl
- Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - Vadim O Chagin
- Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany.,Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia
| | | | | | - M Cristina Cardoso
- Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
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5
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Crosetto N, Bienko M. Radial Organization in the Mammalian Nucleus. Front Genet 2020; 11:33. [PMID: 32117447 PMCID: PMC7028756 DOI: 10.3389/fgene.2020.00033] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 01/10/2020] [Indexed: 11/13/2022] Open
Abstract
In eukaryotic cells, most of the genetic material is contained within a highly specialized organelle-the nucleus. A large body of evidence indicates that, within the nucleus, chromatinized DNA is spatially organized at multiple length scales. The higher-order organization of chromatin is crucial for proper execution of multiple genome functions, including DNA replication and transcription. Here, we review our current knowledge on the spatial organization of chromatin in the nucleus of mammalian cells, focusing in particular on how chromatin is radially arranged with respect to the nuclear lamina. We then discuss the possible mechanisms by which the radial organization of chromatin in the cell nucleus is established. Lastly, we propose a unifying model of nuclear spatial organization, and suggest novel approaches to test it.
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Affiliation(s)
| | - Magda Bienko
- Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
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6
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Feodorova Y, Falk M, Mirny LA, Solovei I. Viewing Nuclear Architecture through the Eyes of Nocturnal Mammals. Trends Cell Biol 2020; 30:276-289. [PMID: 31980345 DOI: 10.1016/j.tcb.2019.12.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 12/10/2019] [Accepted: 12/19/2019] [Indexed: 01/09/2023]
Abstract
The cell nucleus is a remarkably well-organized organelle with membraneless but distinct compartments of various functions. The largest of them, euchromatin and heterochromatin, are spatially segregated in such a way that the transcriptionally active genome occupies the nuclear interior, whereas silent genomic loci are preferentially associated with the nuclear envelope. This rule is broken by rod photoreceptor cells of nocturnal mammals, in which the two major compartments have inverted positions. The inversion and dense compaction of heterochromatin converts these nuclei into microlenses that focus light and facilitate nocturnal vision. As is often the case in biology, when a mutation helps to understand normal processes and structures, inverted nuclei have served as a tool to unravel general principles of nuclear organization, including mechanisms of heterochromatin tethering to the nuclear envelope, autonomous behavior of small genomic segments, and euchromatin-heterochromatin segregation.
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Affiliation(s)
- Yana Feodorova
- Biozentrum, Ludwig-Maximilians University Munich, Grosshadernerstrasse 2, 82152 Planegg-Martinsried, Germany; Department of Medical Biology, Medical University-Plovdiv, Boulevard Vasil Aprilov 15A, Plovdiv 4000, Bulgaria
| | - Martin Falk
- Institute for Medical Engineering and Science, and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Physics, University of Chicago, 929 E 57th St, Chicago, IL 60637, USA
| | - Leonid A Mirny
- Institute for Medical Engineering and Science, and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Irina Solovei
- Biozentrum, Ludwig-Maximilians University Munich, Grosshadernerstrasse 2, 82152 Planegg-Martinsried, Germany.
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7
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4C-seq from beginning to end: A detailed protocol for sample preparation and data analysis. Methods 2020; 170:17-32. [DOI: 10.1016/j.ymeth.2019.07.014] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 07/14/2019] [Indexed: 12/31/2022] Open
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8
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Transcription factors and 3D genome conformation in cell-fate decisions. Nature 2019; 569:345-354. [PMID: 31092938 DOI: 10.1038/s41586-019-1182-7] [Citation(s) in RCA: 290] [Impact Index Per Article: 58.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 03/19/2019] [Indexed: 12/31/2022]
Abstract
How cells adopt different identities has long fascinated biologists. Signal transduction in response to environmental cues results in the activation of transcription factors that determine the gene-expression program characteristic of each cell type. Technological advances in the study of 3D chromatin folding are bringing the role of genome conformation in transcriptional regulation to the fore. Characterizing this role of genome architecture has profound implications, not only for differentiation and development but also for diseases including developmental malformations and cancer. Here we review recent studies indicating that the interplay between transcription and genome conformation is a driving force for cell-fate decisions.
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Denker A, de Laat W. The second decade of 3C technologies: detailed insights into nuclear organization. Genes Dev 2017; 30:1357-82. [PMID: 27340173 PMCID: PMC4926860 DOI: 10.1101/gad.281964.116] [Citation(s) in RCA: 225] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The relevance of three-dimensional (3D) genome organization for transcriptional regulation and thereby for cellular fate at large is now widely accepted. Our understanding of the fascinating architecture underlying this function is based on microscopy studies as well as the chromosome conformation capture (3C) methods, which entered the stage at the beginning of the millennium. The first decade of 3C methods rendered unprecedented insights into genome topology. Here, we provide an update of developments and discoveries made over the more recent years. As we discuss, established and newly developed experimental and computational methods enabled identification of novel, functionally important chromosome structures. Regulatory and architectural chromatin loops throughout the genome are being cataloged and compared between cell types, revealing tissue invariant and developmentally dynamic loops. Architectural proteins shaping the genome were disclosed, and their mode of action is being uncovered. We explain how more detailed insights into the 3D genome increase our understanding of transcriptional regulation in development and misregulation in disease. Finally, to help researchers in choosing the approach best tailored for their specific research question, we explain the differences and commonalities between the various 3C-derived methods.
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Affiliation(s)
- Annette Denker
- Hubrecht Institute-Koninklijke Nederlandse Akademie van Wetenschappen (KNAW) and University Medical Center Utrecht, 3584CT Utrecht, the Netherlands
| | - Wouter de Laat
- Hubrecht Institute-Koninklijke Nederlandse Akademie van Wetenschappen (KNAW) and University Medical Center Utrecht, 3584CT Utrecht, the Netherlands
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10
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van de Werken HJG, Haan JC, Feodorova Y, Bijos D, Weuts A, Theunis K, Holwerda SJB, Meuleman W, Pagie L, Thanisch K, Kumar P, Leonhardt H, Marynen P, van Steensel B, Voet T, de Laat W, Solovei I, Joffe B. Small chromosomal regions position themselves autonomously according to their chromatin class. Genome Res 2017; 27:922-933. [PMID: 28341771 PMCID: PMC5453326 DOI: 10.1101/gr.213751.116] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 03/22/2017] [Indexed: 11/24/2022]
Abstract
The spatial arrangement of chromatin is linked to the regulation of nuclear processes. One striking aspect of nuclear organization is the spatial segregation of heterochromatic and euchromatic domains. The mechanisms of this chromatin segregation are still poorly understood. In this work, we investigated the link between the primary genomic sequence and chromatin domains. We analyzed the spatial intranuclear arrangement of a human artificial chromosome (HAC) in a xenospecific mouse background in comparison to an orthologous region of native mouse chromosome. The two orthologous regions include segments that can be assigned to three major chromatin classes according to their gene abundance and repeat repertoire: (1) gene-rich and SINE-rich euchromatin; (2) gene-poor and LINE/LTR-rich heterochromatin; and (3) gene-depleted and satellite DNA-containing constitutive heterochromatin. We show, using fluorescence in situ hybridization (FISH) and 4C-seq technologies, that chromatin segments ranging from 0.6 to 3 Mb cluster with segments of the same chromatin class. As a consequence, the chromatin segments acquire corresponding positions in the nucleus irrespective of their chromosomal context, thereby strongly suggesting that this is their autonomous property. Interactions with the nuclear lamina, although largely retained in the HAC, reveal less autonomy. Taken together, our results suggest that building of a functional nucleus is largely a self-organizing process based on mutual recognition of chromosome segments belonging to the major chromatin classes.
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Affiliation(s)
- Harmen J G van de Werken
- Cancer Computational Biology Center, Erasmus MC Cancer Institute & Department of Urology, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3015 CN, Rotterdam, The Netherlands.,Hubrecht Institute-KNAW & University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands
| | - Josien C Haan
- Laboratory of Reproductive Genomics, Department of Human Genetics, KU Leuven, Leuven, 3000, Belgium
| | - Yana Feodorova
- Department of Biology II, Ludwig Maximilians University Munich, 82152 Planegg-Martinsried, Germany
| | - Dominika Bijos
- Division of Gene Regulation, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | - An Weuts
- Laboratory of Reproductive Genomics, Department of Human Genetics, KU Leuven, Leuven, 3000, Belgium
| | - Koen Theunis
- Laboratory of Reproductive Genomics, Department of Human Genetics, KU Leuven, Leuven, 3000, Belgium
| | - Sjoerd J B Holwerda
- Hubrecht Institute-KNAW & University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands
| | - Wouter Meuleman
- Division of Gene Regulation, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | - Ludo Pagie
- Division of Gene Regulation, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | - Katharina Thanisch
- Department of Biology II, Ludwig Maximilians University Munich, 82152 Planegg-Martinsried, Germany
| | - Parveen Kumar
- Laboratory of Reproductive Genomics, Department of Human Genetics, KU Leuven, Leuven, 3000, Belgium
| | - Heinrich Leonhardt
- Department of Biology II, Ludwig Maximilians University Munich, 82152 Planegg-Martinsried, Germany
| | - Peter Marynen
- Human Genome Laboratory, Department of Human Genetics, KU Leuven, Leuven, 3000, Belgium
| | - Bas van Steensel
- Division of Gene Regulation, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | - Thierry Voet
- Laboratory of Reproductive Genomics, Department of Human Genetics, KU Leuven, Leuven, 3000, Belgium
| | - Wouter de Laat
- Hubrecht Institute-KNAW & University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands
| | - Irina Solovei
- Department of Biology II, Ludwig Maximilians University Munich, 82152 Planegg-Martinsried, Germany
| | - Boris Joffe
- Department of Biology II, Ludwig Maximilians University Munich, 82152 Planegg-Martinsried, Germany
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11
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Abstract
Genetic variation associated with disease often appears in non-coding parts of the genome. Understanding the mechanisms by which this phenomenon leads to disease is necessary to translate results from genetic association studies to the clinic. Assigning function to this type of variation is notoriously difficult because the human genome harbours a complex regulatory landscape with a dizzying array of transcriptional regulatory sequences, such as enhancers that have unpredictable, promiscuous and context-dependent behaviour. In this Review, we discuss how technological advances have provided increasingly detailed information on genome folding; for example, genome folding forms loops that bring enhancers and target genes into close proximity. We also now know that enhancers function within topologically associated domains, which are structural and functional units of chromosomes. Studying disease-associated mutations and chromosomal rearrangements in the context of the 3D genome will enable the identification of dysregulated target genes and aid the progression from descriptive genetic association results to discovering molecular mechanisms underlying disease.
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12
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Maslova A, Zlotina A, Kosyakova N, Sidorova M, Krasikova A. Three-dimensional architecture of tandem repeats in chicken interphase nucleus. Chromosome Res 2016; 23:625-39. [PMID: 26316311 DOI: 10.1007/s10577-015-9485-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Tandem repeats belong to a class of genomic repetitive elements that form arrays of head-to-tail monomers. Due to technical difficulties in sequencing and assembly of large tandem repeat arrays, it remains largely unknown by which mechanisms tandem-repeat-containing regions aid in maintenance of ordered radial genome organization during interphase. Here we analyzed spatial distribution of several types of tandem repeats in interphase nuclei of chicken MDCC-MSB1 cells and somatic tissues relative to heterochromatin compartments and nuclear center. We showed that telomere and subtelomere repeats generally localize at the nuclear or chromocenters periphery. A tandem repeat known as CNM, typical for centromere regions of gene-dense microchromosomes, forms interchromosome clusters and occupies DAPI-positive chromocenters that appear predominantly within the nuclear interior. In contrast, centromere-specific tandem repeats of the majority of gene-poor macrochromosomes are embedded into the peripheral layer of heterochromatin. Chicken chromocenters rarely comprise centromere sequences of both macro- and microchromosomes, whose territories localize in different radial nuclear zones. Possible mechanisms of observed tandem repeats positioning and its implication in highly ordered arrangement of chromosome territories in chicken interphase nucleus are discussed.
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Affiliation(s)
- Antonina Maslova
- Saint Petersburg State University, Saint Petersburg, 198504, Russia
| | - Anna Zlotina
- Saint Petersburg State University, Saint Petersburg, 198504, Russia
| | - Nadezhda Kosyakova
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Marina Sidorova
- Saint Petersburg State University, Saint Petersburg, 198504, Russia
| | - Alla Krasikova
- Saint Petersburg State University, Saint Petersburg, 198504, Russia.
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13
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Single-cell genome-wide studies give new insight into nongenetic cell-to-cell variability in animals. Histochem Cell Biol 2016; 146:239-54. [DOI: 10.1007/s00418-016-1466-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2016] [Indexed: 01/21/2023]
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14
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Liquid-like behavior of chromatin. Curr Opin Genet Dev 2016; 37:36-45. [DOI: 10.1016/j.gde.2015.11.006] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 11/23/2015] [Accepted: 11/25/2015] [Indexed: 11/23/2022]
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15
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Dekker J, Mirny L. The 3D Genome as Moderator of Chromosomal Communication. Cell 2016; 164:1110-1121. [PMID: 26967279 PMCID: PMC4788811 DOI: 10.1016/j.cell.2016.02.007] [Citation(s) in RCA: 606] [Impact Index Per Article: 75.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 01/22/2016] [Accepted: 02/01/2016] [Indexed: 02/07/2023]
Abstract
Proper expression of genes requires communication with their regulatory elements that can be located elsewhere along the chromosome. The physics of chromatin fibers imposes a range of constraints on such communication. The molecular and biophysical mechanisms by which chromosomal communication is established, or prevented, have become a topic of intense study, and important roles for the spatial organization of chromosomes are being discovered. Here we present a view of the interphase 3D genome characterized by extensive physical compartmentalization and insulation on the one hand and facilitated long-range interactions on the other. We propose the existence of topological machines dedicated to set up and to exploit a 3D genome organization to both promote and censor communication along and between chromosomes.
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Affiliation(s)
- Job Dekker
- Howard Hughes Medical Institute, Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605-0103, USA.
| | - Leonid Mirny
- Institute for Medical Engineering and Science and Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, E25-526C, Cambridge, MA 02139, USA.
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16
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Solovei I, Thanisch K, Feodorova Y. How to rule the nucleus: divide et impera. Curr Opin Cell Biol 2016; 40:47-59. [PMID: 26938331 DOI: 10.1016/j.ceb.2016.02.014] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 02/04/2016] [Accepted: 02/14/2016] [Indexed: 01/14/2023]
Abstract
Genome-wide molecular studies have provided new insights into the organization of nuclear chromatin by revealing the presence of chromatin domains of differing transcriptional activity, frequency of cis-interactions, proximity to scaffolding structures and replication timing. These studies have not only brought our understanding of genome function to a new level, but also offered functional insight for many phenomena observed in microscopic studies. In this review, we discuss the major principles of nuclear organization based on the spatial segregation of euchromatin and heterochromatin, as well as the dynamic genome rearrangements occurring during cell differentiation and development. We hope to unite the existing molecular and microscopic data on genome organization to get a holistic view of the nucleus, and propose a model, in which repeat repertoire together with scaffolding structures blueprint the functional nuclear architecture.
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Affiliation(s)
- Irina Solovei
- Department of Biology II, Ludwig Maximilians University Munich, Grosshadernerstrasse 2, Planegg-Martinsried 82152, Germany.
| | - Katharina Thanisch
- Department of Biology II, Ludwig Maximilians University Munich, Grosshadernerstrasse 2, Planegg-Martinsried 82152, Germany
| | - Yana Feodorova
- Department of Biology II, Ludwig Maximilians University Munich, Grosshadernerstrasse 2, Planegg-Martinsried 82152, Germany; Department of Medical Biology, Medical University-Plovdiv, Boulevard Vasil Aprilov 15A, Plovdiv 4000, Bulgaria
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17
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Wijchers PJ, Krijger PHL, Geeven G, Zhu Y, Denker A, Verstegen MJAM, Valdes-Quezada C, Vermeulen C, Janssen M, Teunissen H, Anink-Groenen LCM, Verschure PJ, de Laat W. Cause and Consequence of Tethering a SubTAD to Different Nuclear Compartments. Mol Cell 2016; 61:461-473. [PMID: 26833089 PMCID: PMC4747903 DOI: 10.1016/j.molcel.2016.01.001] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 10/30/2015] [Accepted: 12/22/2015] [Indexed: 12/11/2022]
Abstract
Detailed genomic contact maps have revealed that chromosomes are structurally organized in megabase-sized topologically associated domains (TADs) that encompass smaller subTADs. These domains segregate in the nuclear space to form active and inactive nuclear compartments, but cause and consequence of compartmentalization are largely unknown. Here, we combined lacO/lacR binding platforms with allele-specific 4C technologies to track their precise position in the three-dimensional genome upon recruitment of NANOG, SUV39H1, or EZH2. We observed locked genomic loci resistant to spatial repositioning and unlocked loci that could be repositioned to different nuclear subcompartments with distinct chromatin signatures. Focal protein recruitment caused the entire subTAD, but not surrounding regions, to engage in new genomic contacts. Compartment switching was found uncoupled from transcription changes, and the enzymatic modification of histones per se was insufficient for repositioning. Collectively, this suggests that trans-associated factors influence three-dimensional compartmentalization independent of their cis effect on local chromatin composition and activity.
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Affiliation(s)
- Patrick J Wijchers
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Peter H L Krijger
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Geert Geeven
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Yun Zhu
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Annette Denker
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Marjon J A M Verstegen
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Christian Valdes-Quezada
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Carlo Vermeulen
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Mark Janssen
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Hans Teunissen
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Lisette C M Anink-Groenen
- Synthetic Systems Biology and Nuclear Organization Group, Swammerdam Institute for Life Sciences, University of Amsterdam, 1098 XH Amsterdam, the Netherlands
| | - Pernette J Verschure
- Synthetic Systems Biology and Nuclear Organization Group, Swammerdam Institute for Life Sciences, University of Amsterdam, 1098 XH Amsterdam, the Netherlands
| | - Wouter de Laat
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands.
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18
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Politz JCR, Scalzo D, Groudine M. The redundancy of the mammalian heterochromatic compartment. Curr Opin Genet Dev 2015; 37:1-8. [PMID: 26706451 DOI: 10.1016/j.gde.2015.10.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 10/26/2015] [Accepted: 10/28/2015] [Indexed: 01/05/2023]
Abstract
Two chromatin compartments are present in most mammalian cells; the first contains primarily euchromatic, early replicating chromatin and the second, primarily late-replicating heterochromatin, which is the subject of this review. Heterochromatin is concentrated in three intranuclear regions: the nuclear periphery, the perinucleolar space and in pericentromeric bodies. We review recent evidence demonstrating that the heterochromatic compartment is critically involved in global nuclear organization and the maintenance of genome stability, and discuss models regarding how this compartment is formed and maintained. We also evaluate our understanding of how heterochromatic sequences (herein named heterochromatic associated regions (HADs)) might be tethered within these regions and review experiments that reveal the stochastic nature of individual HAD positioning within the compartment. These investigations suggest a substantial level of functional redundancy within the heterochromatic compartment.
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Affiliation(s)
| | - David Scalzo
- Fred Hutchinson Cancer Research Center, Seattle, WA, United States
| | - Mark Groudine
- Fred Hutchinson Cancer Research Center, Seattle, WA, United States.
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19
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Roy S, Siahpirani AF, Chasman D, Knaack S, Ay F, Stewart R, Wilson M, Sridharan R. A predictive modeling approach for cell line-specific long-range regulatory interactions. Nucleic Acids Res 2015; 43:8694-712. [PMID: 26338778 PMCID: PMC4605315 DOI: 10.1093/nar/gkv865] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 08/16/2015] [Accepted: 08/17/2015] [Indexed: 01/28/2023] Open
Abstract
Long range regulatory interactions among distal enhancers and target genes are important for tissue-specific gene expression. Genome-scale identification of these interactions in a cell line-specific manner, especially using the fewest possible datasets, is a significant challenge. We develop a novel computational approach, Regulatory Interaction Prediction for Promoters and Long-range Enhancers (RIPPLE), that integrates published Chromosome Conformation Capture (3C) data sets with a minimal set of regulatory genomic data sets to predict enhancer-promoter interactions in a cell line-specific manner. Our results suggest that CTCF, RAD21, a general transcription factor (TBP) and activating chromatin marks are important determinants of enhancer-promoter interactions. To predict interactions in a new cell line and to generate genome-wide interaction maps, we develop an ensemble version of RIPPLE and apply it to generate interactions in five human cell lines. Computational validation of these predictions using existing ChIA-PET and Hi-C data sets showed that RIPPLE accurately predicts interactions among enhancers and promoters. Enhancer-promoter interactions tend to be organized into subnetworks representing coordinately regulated sets of genes that are enriched for specific biological processes and cis-regulatory elements. Overall, our work provides a systematic approach to predict and interpret enhancer-promoter interactions in a genome-wide cell-type specific manner using a few experimentally tractable measurements.
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Affiliation(s)
- Sushmita Roy
- Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, WI, USA Wisconsin Institute for Discovery, 330 N. Orchard Street, Madison, WI, USA
| | | | - Deborah Chasman
- Wisconsin Institute for Discovery, 330 N. Orchard Street, Madison, WI, USA
| | - Sara Knaack
- Wisconsin Institute for Discovery, 330 N. Orchard Street, Madison, WI, USA
| | - Ferhat Ay
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Ron Stewart
- Morgridge Institute for Research, Madison, WI 53715, USA
| | - Michael Wilson
- Genetics & Genome Biology Program, Hospital for Sick Children (SickKids) and Department of Molecular Genetics, University of Toronto,Toronto, ON, Canada Department of Molecular Genetics, University of Toronto, ON, Canada
| | - Rupa Sridharan
- Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, WI, USA Department of Cell and Regenerative biology, University of Wisconsin, Madison, WI 53715, USA
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20
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21
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Bouwman BAM, de Laat W. Getting the genome in shape: the formation of loops, domains and compartments. Genome Biol 2015; 16:154. [PMID: 26257189 PMCID: PMC4536798 DOI: 10.1186/s13059-015-0730-1] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The hierarchical levels of genome architecture exert transcriptional control by tuning the accessibility and proximity of genes and regulatory elements. Here, we review current insights into the trans-acting factors that enable the genome to flexibly adopt different functionally relevant conformations.
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Affiliation(s)
- Britta A M Bouwman
- Hubrecht Institute - KNAW and University Medical Center Utrecht, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands
| | - Wouter de Laat
- Hubrecht Institute - KNAW and University Medical Center Utrecht, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands.
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22
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Functional role of dimerization and CP190 interacting domains of CTCF protein in Drosophila melanogaster. BMC Biol 2015; 13:63. [PMID: 26248466 PMCID: PMC4528719 DOI: 10.1186/s12915-015-0168-7] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 07/15/2015] [Indexed: 12/22/2022] Open
Abstract
Background Insulators play a central role in gene regulation, chromosomal architecture and genome function in higher eukaryotes. To learn more about how insulators carry out their diverse functions, we have begun an analysis of the Drosophila CTCF (dCTCF). CTCF is one of the few insulator proteins known to be conserved from flies to man. Results In the studies reported here we have focused on the identification and characterization of two dCTCF protein interaction modules. The first mediates dCTCF multimerization, while the second mediates dCTCF–CP190 interactions. The multimerization domain maps in the N-terminus of the dCTCF protein and likely mediates the formation of tetrameric complexes. The CP190 interaction module encompasses a sequence ~200 amino acids long that spans the C-terminal and mediates interactions with the N-terminal BTB domain of the CP190 protein. Transgene rescue experiments showed that a dCTCF protein lacking sequences critical for CP190 interactions was almost as effective as wild type in rescuing the phenotypic effects of a dCTCF null allele. The mutation did, however, affect CP190 recruitment to specific Drosophila insulator elements and had a modest effect on dCTCF chromatin association. A protein lacking the N-terminal dCTCF multimerization domain incompletely rescued the zygotic and maternal effect lethality of the null and did not rescue the defects in Abd-B regulation evident in surviving adult dCTCF mutant flies. Finally, we show that elimination of maternally contributed dCTCF at the onset of embryogenesis has quite different effects on development and Abd-B regulation than is observed when the homozygous mutant animals develop in the presence of maternally derived dCTCF activity. Conclusions Our results indicate that dCTCF–CP190 interactions are less critical for the in vivo functions of the dCTCF protein than the N-terminal dCTCF–dCTCF interaction domain. We also show that the phenotypic consequences of dCTCF mutations differ depending upon when and how dCTCF activity is lost. Electronic supplementary material The online version of this article (doi:10.1186/s12915-015-0168-7) contains supplementary material, which is available to authorized users.
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23
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Masaki N, Ishizaki I, Hayasaka T, Fisher GL, Sanada N, Yokota H, Setou M. Three-Dimensional Image of Cleavage Bodies in Nuclei Is Configured Using Gas Cluster Ion Beam with Time-of-Flight Secondary Ion Mass Spectrometry. Sci Rep 2015; 5:10000. [PMID: 25961407 PMCID: PMC4426704 DOI: 10.1038/srep10000] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 03/25/2015] [Indexed: 12/28/2022] Open
Abstract
Structural variations of DNA in nuclei are deeply related with development, aging, and diseases through transcriptional regulation. In order to bare cross sections of samples maintaining sub-micron structures, an Ar2500+-gas cluster ion beam (GCIB) sputter was recently engineered. By introducing GCIB sputter to time-of-flight secondary ion mass spectrometry (TOF-SIMS), we analyzed the 3D configuration and chemical composition of subnuclear structures of pyramidal cells in the CA2 region in mouse brain hippocampus. Depth profiles of chemicals were analyzed as 3D distributions by combining topographic analyses. Signals corresponding to anions such as CN− and PO3− were distributed characteristically in the shape of cell organelles. CN− signals overlapped DAPI fluorescence signals corresponding to nuclei. The clusters shown by PO3− and those of adenine ions were colocalized inside nuclei revealed by the 3D reconstruction. Taking into account their size and their number in each nucleus, those clusters could be in the cleavage bodies, which are a kind of intranuclear structure.
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Affiliation(s)
- Noritaka Masaki
- Dept of Cell Biology and Anatomy, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan
| | | | - Takahiro Hayasaka
- Dept of Cell Biology and Anatomy, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan
| | - Gregory L Fisher
- Physical Electronics, 18725 Lake Drive East, Chanhassen, MN 55317, USA
| | - Noriaki Sanada
- ULVAC-PHI, 370 Enzo, Chigasaki, Kanagawa 253-8522, Japan
| | - Hideo Yokota
- Image Processing Research Team, Center for Advanced Photonics, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Mitsutoshi Setou
- Dept of Cell Biology and Anatomy, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan
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24
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Architectural hallmarks of the pluripotent genome. FEBS Lett 2015; 589:2905-13. [PMID: 25957773 DOI: 10.1016/j.febslet.2015.04.055] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Revised: 04/24/2015] [Accepted: 04/27/2015] [Indexed: 01/03/2023]
Abstract
Pluripotent stem cells (PSCs) have the ability to self-renew and are capable of generating all embryonic germ layers (Evans and Kaufman, 1981; Thomson et al., 1998). PSCs can be isolated from early embryos or may be induced via overexpression of pluripotency transcription factors in differentiated cells (Takahashi and Yamanaka, 2006). As PSCs hold great promise for regenerative medicine, the mechanisms underlying pluripotency and induction thereof are studied intensively. Pluripotency is characterized by a unique transcriptional program that is in part controlled by an exceptionally plastic regulatory chromatin landscape. In recent years, 3D genome configuration has emerged as an important regulator of transcriptional control and cellular identity (Taddei et al., 2004 [4]; Lanctot et al., 2007 [5]; Gibcus and Dekker, 2013; Misteli, 2009 [7]). Here we provide an overview of recent findings on the 3D genome organization in PSCs and discuss its putative functional role in regulation of the pluripotent state.
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25
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Wijchers PJ, Geeven G, Eyres M, Bergsma AJ, Janssen M, Verstegen M, Zhu Y, Schell Y, Vermeulen C, de Wit E, de Laat W. Characterization and dynamics of pericentromere-associated domains in mice. Genome Res 2015; 25:958-69. [PMID: 25883320 PMCID: PMC4484393 DOI: 10.1101/gr.186643.114] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 04/13/2015] [Indexed: 01/01/2023]
Abstract
Despite recent progress in genome topology knowledge, the role of repeats, which make up the majority of mammalian genomes, remains elusive. Satellite repeats are highly abundant sequences that cluster around centromeres, attract pericentromeric heterochromatin, and aggregate into nuclear chromocenters. These nuclear landmark structures are assumed to form a repressive compartment in the nucleus to which genes are recruited for silencing. We have designed a strategy for genome-wide identification of pericentromere-associated domains (PADs) in different mouse cell types. The ∼1000 PADs and non-PADs have similar chromatin states in embryonic stem cells, but during lineage commitment, chromocenters progressively associate with constitutively inactive genomic regions at the nuclear periphery. This suggests that PADs are not actively recruited to chromocenters, but that chromocenters are themselves attracted to inactive chromatin compartments. However, we also found that experimentally induced proximity of an active locus to chromocenters was sufficient to cause gene repression. Collectively, our data suggest that rather than driving nuclear organization, pericentromeric satellite repeats mostly co-segregate with inactive genomic regions into nuclear compartments where they can contribute to stable maintenance of the repressed status of proximal chromosomal regions.
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Affiliation(s)
- Patrick J Wijchers
- Hubrecht Institute-KNAW & University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands
| | - Geert Geeven
- Hubrecht Institute-KNAW & University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands
| | - Michael Eyres
- Hubrecht Institute-KNAW & University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands
| | - Atze J Bergsma
- Hubrecht Institute-KNAW & University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands
| | - Mark Janssen
- Hubrecht Institute-KNAW & University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands
| | - Marjon Verstegen
- Hubrecht Institute-KNAW & University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands
| | - Yun Zhu
- Hubrecht Institute-KNAW & University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands
| | - Yori Schell
- Hubrecht Institute-KNAW & University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands
| | - Carlo Vermeulen
- Hubrecht Institute-KNAW & University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands
| | - Elzo de Wit
- Hubrecht Institute-KNAW & University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands
| | - Wouter de Laat
- Hubrecht Institute-KNAW & University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands
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26
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Stratigi K, Kapsetaki M, Aivaliotis M, Town T, Flavell RA, Spilianakis CG. Spatial proximity of homologous alleles and long noncoding RNAs regulate a switch in allelic gene expression. Proc Natl Acad Sci U S A 2015; 112:E1577-86. [PMID: 25770217 PMCID: PMC4386343 DOI: 10.1073/pnas.1502182112] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Physiological processes rely on the regulation of total mRNA levels in a cell. In diploid organisms, the transcriptional activation of one or both alleles of a gene may involve trans-allelic interactions that provide a tight spatial and temporal level of gene expression regulation. The mechanisms underlying such interactions still remain poorly understood. Here, we demonstrate that lipopolysaccharide stimulation of murine macrophages rapidly resulted in the actin-mediated and transient homologous spatial proximity of Tnfα alleles, which was necessary for the mono- to biallelic switch in gene expression. We identified two new complementary long noncoding RNAs transcribed from the TNFα locus and showed that their knockdown had opposite effects in Tnfα spatial proximity and allelic expression. Moreover, the observed spatial proximity of Tnfα alleles depended on pyruvate kinase muscle isoform 2 (PKM2) and T-helper-inducing POZ-Krüppel-like factor (ThPOK). This study suggests a role for lncRNAs in the regulation of somatic homologous spatial proximity and allelic expression control necessary for fine-tuning mammalian immune responses.
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Affiliation(s)
- Kalliopi Stratigi
- Institute of Molecular Biology and Biotechnology-Foundation for Research and Technology Hellas, GR70013 Heraklion, Greece; Department of Biology, University of Crete, GR70013 Heraklion, Greece
| | - Manouela Kapsetaki
- Institute of Molecular Biology and Biotechnology-Foundation for Research and Technology Hellas, GR70013 Heraklion, Greece
| | - Michalis Aivaliotis
- Institute of Molecular Biology and Biotechnology-Foundation for Research and Technology Hellas, GR70013 Heraklion, Greece
| | - Terrence Town
- Department of Physiology and Biophysics, Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90089; and
| | - Richard A Flavell
- Department of Immunobiology and Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06520
| | - Charalampos G Spilianakis
- Institute of Molecular Biology and Biotechnology-Foundation for Research and Technology Hellas, GR70013 Heraklion, Greece; Department of Biology, University of Crete, GR70013 Heraklion, Greece;
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27
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Ibn-Salem J, Köhler S, Love MI, Chung HR, Huang N, Hurles ME, Haendel M, Washington NL, Smedley D, Mungall CJ, Lewis SE, Ott CE, Bauer S, Schofield PN, Mundlos S, Spielmann M, Robinson PN. Deletions of chromosomal regulatory boundaries are associated with congenital disease. Genome Biol 2014; 15:423. [PMID: 25315429 PMCID: PMC4180961 DOI: 10.1186/s13059-014-0423-1] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 07/24/2014] [Indexed: 12/21/2022] Open
Abstract
Background Recent data from genome-wide chromosome conformation capture analysis indicate that the human genome is divided into conserved megabase-sized self-interacting regions called topological domains. These topological domains form the regulatory backbone of the genome and are separated by regulatory boundary elements or barriers. Copy-number variations can potentially alter the topological domain architecture by deleting or duplicating the barriers and thereby allowing enhancers from neighboring domains to ectopically activate genes causing misexpression and disease, a mutational mechanism that has recently been termed enhancer adoption. Results We use the Human Phenotype Ontology database to relate the phenotypes of 922 deletion cases recorded in the DECIPHER database to monogenic diseases associated with genes in or adjacent to the deletions. We identify combinations of tissue-specific enhancers and genes adjacent to the deletion and associated with phenotypes in the corresponding tissue, whereby the phenotype matched that observed in the deletion. We compare this computationally with a gene-dosage pathomechanism that attempts to explain the deletion phenotype based on haploinsufficiency of genes located within the deletions. Up to 11.8% of the deletions could be best explained by enhancer adoption or a combination of enhancer adoption and gene-dosage effects. Conclusions Our results suggest that enhancer adoption caused by deletions of regulatory boundaries may contribute to a substantial minority of copy-number variation phenotypes and should thus be taken into account in their medical interpretation. Electronic supplementary material The online version of this article (doi:10.1186/s13059-014-0423-1) contains supplementary material, which is available to authorized users.
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28
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Luo C, Dong J, Zhang Y, Lam E. Decoding the role of chromatin architecture in development: coming closer to the end of the tunnel. FRONTIERS IN PLANT SCIENCE 2014; 5:374. [PMID: 25191327 PMCID: PMC4140164 DOI: 10.3389/fpls.2014.00374] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Accepted: 07/11/2014] [Indexed: 06/03/2023]
Abstract
Form and function in biology are intimately related aspects that are often difficult to untangle. While the structural aspects of chromatin organization were apparent from early cytological observations long before the molecular details of chromatin functions were deciphered, the extent to which genome architecture may impact its output remains unclear. A major roadblock to resolve this issue is the divergent scales, both temporal and spatial, of the experimental approaches for examining these facets of chromatin biology. Recent advances in high-throughput sequencing and informatics to model and monitor genome-wide chromatin contact sites provide the much-needed platform to close this gap. This mini-review will focus on discussing recent efforts applying new technologies to elucidate the roles of genome architecture in coordinating global gene expression output. Our discussion will emphasize the potential roles of differential genome 3-D structure as a driver for cell fate specification of multicellular organisms. An integrated approach that combines multiple new methodologies may finally have the necessary temporal and spatial resolution to provide clarity on the roles of chromatin architecture during development.
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Affiliation(s)
- Chongyuan Luo
- Department of Plant Biology and Pathology, Rutgers the State University of New JerseyNew Brunswick, NJ, USA
| | - Juan Dong
- Department of Plant Biology and Pathology, Rutgers the State University of New JerseyNew Brunswick, NJ, USA
- The Waksman Institute of Microbiology, Rutgers the State University of New JerseyPiscataway, NJ, USA
| | - Yi Zhang
- Department of Plant Biology and Pathology, Rutgers the State University of New JerseyNew Brunswick, NJ, USA
| | - Eric Lam
- Department of Plant Biology and Pathology, Rutgers the State University of New JerseyNew Brunswick, NJ, USA
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29
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Maksimenko O, Kyrchanova O, Bonchuk A, Stakhov V, Parshikov A, Georgiev P. Highly conserved ENY2/Sus1 protein binds to Drosophila CTCF and is required for barrier activity. Epigenetics 2014; 9:1261-70. [PMID: 25147918 DOI: 10.4161/epi.32086] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Chromatin insulators affect interactions between promoters and enhancers/silencers and function as barriers for the spreading of repressive chromatin. Drosophila insulator protein dCTCF marks active promoters and boundaries of many histone H3K27 trimethylation domains associated with repressed chromatin. In particular, dCTCF binds to such boundaries between the parasegment-specific regulatory domains of the Bithorax complex. Here we demonstrate that the evolutionarily conserved protein ENY2 is recruited to the zinc-finger domain of dCTCF and is required for the barrier activity of dCTCF-dependent insulators in transgenic lines. Inactivation of ENY2 by RNAi in BG3 cells leads to the spreading of H3K27 trimethylation and Pc protein at several dCTCF boundaries. The results suggest that evolutionarily conserved ENY2 is responsible for barrier activity mediated by the dCTCF protein.
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Affiliation(s)
- Oksana Maksimenko
- Laboratory of Gene Expression Regulation in Development; Institute of Gene Biology; Russian Academy of Sciences; Moscow, Russia
| | - Olga Kyrchanova
- Group of Transcriptional Regulation; Institute of Gene Biology; Russian Academy of Sciences; Moscow, Russia
| | - Artem Bonchuk
- Group of Transcriptional Regulation; Institute of Gene Biology; Russian Academy of Sciences; Moscow, Russia
| | - Viacheslav Stakhov
- Laboratory of Gene Expression Regulation in Development; Institute of Gene Biology; Russian Academy of Sciences; Moscow, Russia
| | - Alexander Parshikov
- Department of the Control of Genetic Processes; Institute of Gene Biology; Russian Academy of Sciences; Moscow, Russia
| | - Pavel Georgiev
- Department of the Control of Genetic Processes; Institute of Gene Biology; Russian Academy of Sciences; Moscow, Russia
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Giorgetti L, Galupa R, Nora EP, Piolot T, Lam F, Dekker J, Tiana G, Heard E. Predictive polymer modeling reveals coupled fluctuations in chromosome conformation and transcription. Cell 2014; 157:950-63. [PMID: 24813616 DOI: 10.1016/j.cell.2014.03.025] [Citation(s) in RCA: 327] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 12/02/2013] [Accepted: 03/06/2014] [Indexed: 11/16/2022]
Abstract
A new level of chromosome organization, topologically associating domains (TADs), was recently uncovered by chromosome conformation capture (3C) techniques. To explore TAD structure and function, we developed a polymer model that can extract the full repertoire of chromatin conformations within TADs from population-based 3C data. This model predicts actual physical distances and to what extent chromosomal contacts vary between cells. It also identifies interactions within single TADs that stabilize boundaries between TADs and allows us to identify and genetically validate key structural elements within TADs. Combining the model's predictions with high-resolution DNA FISH and quantitative RNA FISH for TADs within the X-inactivation center (Xic), we dissect the relationship between transcription and spatial proximity to cis-regulatory elements. We demonstrate that contacts between potential regulatory elements occur in the context of fluctuating structures rather than stable loops and propose that such fluctuations may contribute to asymmetric expression in the Xic during X inactivation.
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Affiliation(s)
- Luca Giorgetti
- Institut Curie, 26 Rue d'Ulm, 75248 Paris Cedex 05, France; CNRS UMR3215, 75248 Paris Cedex 05, France; INSERM U934, 75248 Paris Cedex 05, France
| | - Rafael Galupa
- Institut Curie, 26 Rue d'Ulm, 75248 Paris Cedex 05, France; CNRS UMR3215, 75248 Paris Cedex 05, France; INSERM U934, 75248 Paris Cedex 05, France
| | - Elphège P Nora
- Institut Curie, 26 Rue d'Ulm, 75248 Paris Cedex 05, France
| | - Tristan Piolot
- Institut Curie, 26 Rue d'Ulm, 75248 Paris Cedex 05, France; CNRS UMR3215, 75248 Paris Cedex 05, France; INSERM U934, 75248 Paris Cedex 05, France
| | - France Lam
- Institut Curie, 26 Rue d'Ulm, 75248 Paris Cedex 05, France; CNRS UMR3215, 75248 Paris Cedex 05, France; INSERM U934, 75248 Paris Cedex 05, France
| | - Job Dekker
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA 01605-0103, USA
| | - Guido Tiana
- Dipartimento di Fisica, Università degli Studi di Milano and INFN, Via Celoria 16, 20133 Milano, Italy.
| | - Edith Heard
- Institut Curie, 26 Rue d'Ulm, 75248 Paris Cedex 05, France; CNRS UMR3215, 75248 Paris Cedex 05, France; INSERM U934, 75248 Paris Cedex 05, France; Collège de France, 11 place Marcelin-Berthelot, Paris 75005, France.
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Dowen JM, Young RA. SMC complexes link gene expression and genome architecture. Curr Opin Genet Dev 2014; 25:131-7. [PMID: 24794701 PMCID: PMC4045092 DOI: 10.1016/j.gde.2013.11.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2013] [Revised: 11/14/2013] [Accepted: 11/15/2013] [Indexed: 12/15/2022]
Abstract
The structural maintenance of chromosomes (SMC) complexes are associated with transcriptional enhancers, promoters and insulators, where they contribute to the control of gene expression and genome structure. We review here recent insights into the interlinked roles of SMC complexes in gene expression and genome architecture. Among these, we note evidence that SMC complexes play important roles in the regulation of genes that control cell identity. We conclude by reviewing diseases associated with SMC mutations.
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Affiliation(s)
- Jill M Dowen
- Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, United States
| | - Richard A Young
- Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, United States; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, United States.
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32
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Schierding W, Cutfield WS, O'Sullivan JM. The missing story behind Genome Wide Association Studies: single nucleotide polymorphisms in gene deserts have a story to tell. Front Genet 2014; 5:39. [PMID: 24600475 PMCID: PMC3927098 DOI: 10.3389/fgene.2014.00039] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 01/31/2014] [Indexed: 11/13/2022] Open
Abstract
Genome wide association studies are central to the evolution of personalized medicine. However, the propensity for single nucleotide polymorphisms (SNPs) to fall outside of genes means that understanding how these polymorphisms alter cellular function requires an expanded view of human genetics. Integrating the study of genome structure (chromosome conformation capture) into its function opens up new avenues of exploration. Changes in the epigenome associated with SNPs in gene deserts will allow us to define complex diseases in a much clearer manner, and usher in a new era of disease pathway exploration.
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Affiliation(s)
| | - Wayne S. Cutfield
- Liggins Institute, University of AucklandAuckland, New Zealand
- Gravida – National Centre for Growth and DevelopmentAuckland, New Zealand
| | - Justin M. O'Sullivan
- Liggins Institute, University of AucklandAuckland, New Zealand
- Gravida – National Centre for Growth and DevelopmentAuckland, New Zealand
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Maksimenko O, Georgiev P. Mechanisms and proteins involved in long-distance interactions. Front Genet 2014; 5:28. [PMID: 24600469 PMCID: PMC3927085 DOI: 10.3389/fgene.2014.00028] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 01/25/2014] [Indexed: 12/28/2022] Open
Abstract
Due to advances in genome-wide technologies, consistent distant interactions within chromosomes of higher eukaryotes have been revealed. In particular, it has been shown that enhancers can specifically and directly interact with promoters by looping out intervening sequences, which can be up to several hundred kilobases long. This review is focused on transcription factors that are supposed to be involved in long-range interactions. Available data are in agreement with the model that several known transcription factors and insulator proteins belong to an abundant but poorly studied class of proteins that are responsible for chromosomal architecture.
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Affiliation(s)
- Oksana Maksimenko
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences Moscow, Russia
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences Moscow, Russia
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Relevance and limitations of crowding, fractal, and polymer models to describe nuclear architecture. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 307:443-79. [PMID: 24380602 DOI: 10.1016/b978-0-12-800046-5.00013-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Chromosome architecture plays an essential role for all nuclear functions, and its physical description has attracted considerable interest over the last few years among the biophysics community. These researches at the frontiers of physics and biology have been stimulated by the demand for quantitative analysis of molecular biology experiments, which provide comprehensive data on chromosome folding, or of live cell imaging experiments that enable researchers to visualize selected chromosome loci in living or fixed cells. In this review our goal is to survey several nonmutually exclusive models that have emerged to describe the folding of DNA in the nucleus, the dynamics of proteins in the nucleoplasm, or the movements of chromosome loci. We focus on three classes of models, namely molecular crowding, fractal, and polymer models, draw comparisons, and discuss their merits and limitations in the context of chromosome structure and dynamics, or nuclear protein navigation in the nucleoplasm. Finally, we identify future challenges in the roadmap to a unified model of the nuclear environment.
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Enkhmandakh B, Bayarsaihan D. 3D genome architecture in the mammalian nucleus. Epigenomics 2013; 5:599-601. [PMID: 24283872 DOI: 10.2217/epi.13.64] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Affiliation(s)
- Badam Enkhmandakh
- Center for Regenerative Medicine & Skeletal Development, Department of Reconstructive Sciences, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030, USA
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36
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de Wit E, Bouwman BAM, Zhu Y, Klous P, Splinter E, Verstegen MJAM, Krijger PHL, Festuccia N, Nora EP, Welling M, Heard E, Geijsen N, Poot RA, Chambers I, de Laat W. The pluripotent genome in three dimensions is shaped around pluripotency factors. Nature 2013; 501:227-31. [PMID: 23883933 DOI: 10.1038/nature12420] [Citation(s) in RCA: 190] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 06/26/2013] [Indexed: 01/06/2023]
Abstract
It is becoming increasingly clear that the shape of the genome importantly influences transcription regulation. Pluripotent stem cells such as embryonic stem cells were recently shown to organize their chromosomes into topological domains that are largely invariant between cell types. Here we combine chromatin conformation capture technologies with chromatin factor binding data to demonstrate that inactive chromatin is unusually disorganized in pluripotent stem-cell nuclei. We show that gene promoters engage in contacts between topological domains in a largely tissue-independent manner, whereas enhancers have a more tissue-restricted interaction profile. Notably, genomic clusters of pluripotency factor binding sites find each other very efficiently, in a manner that is strictly pluripotent-stem-cell-specific, dependent on the presence of Oct4 and Nanog protein and inducible after artificial recruitment of Nanog to a selected chromosomal site. We conclude that pluripotent stem cells have a unique higher-order genome structure shaped by pluripotency factors. We speculate that this interactome enhances the robustness of the pluripotent state.
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Affiliation(s)
- Elzo de Wit
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
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Nora EP, Dekker J, Heard E. Segmental folding of chromosomes: a basis for structural and regulatory chromosomal neighborhoods? Bioessays 2013; 35:818-28. [PMID: 23832846 PMCID: PMC3874840 DOI: 10.1002/bies.201300040] [Citation(s) in RCA: 141] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We discuss here a series of testable hypotheses concerning the role of chromosome folding into topologically associating domains (TADs). Several lines of evidence suggest that segmental packaging of chromosomal neighborhoods may underlie features of chromatin that span large domains, such as heterochromatin blocks, association with the nuclear lamina and replication timing. By defining which DNA elements preferentially contact each other, the segmentation of chromosomes into TADs may also underlie many properties of long-range transcriptional regulation. Several observations suggest that TADs can indeed provide a structural basis to regulatory landscapes, by controlling enhancer sharing and allocation. We also discuss how TADs may shape the evolution of chromosomes, by causing maintenance of synteny over large chromosomal segments. Finally we suggest a series of experiments to challenge these ideas and provide concrete examples illustrating how they could be practically applied.
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39
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Ritland Politz JC, Scalzo D, Groudine M. Something silent this way forms: the functional organization of the repressive nuclear compartment. Annu Rev Cell Dev Biol 2013; 29:241-70. [PMID: 23834025 PMCID: PMC3999972 DOI: 10.1146/annurev-cellbio-101512-122317] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The repressive compartment of the nucleus is comprised primarily of telomeric and centromeric regions, the silent portion of ribosomal RNA genes, the majority of transposable element repeats, and facultatively repressed genes specific to different cell types. This compartment localizes into three main regions: the peripheral heterochromatin, perinucleolar heterochromatin, and pericentromeric heterochromatin. Both chromatin remodeling proteins and transcription of noncoding RNAs are involved in maintenance of repression in these compartments. Global reorganization of the repressive compartment occurs at each cell division, during early development, and during terminal differentiation. Differential action of chromatin remodeling complexes and boundary element looping activities are involved in mediating these organizational changes. We discuss the evidence that heterochromatin formation and compartmentalization may drive nuclear organization.
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Affiliation(s)
| | - David Scalzo
- Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
| | - Mark Groudine
- Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
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